Metallic-State Ti 2 O with Polarized Motifs Boosting Efficient Ammonia Electrosynthesis

Transition metal oxides with tailored polar architectures are vital for tuning electrocatalytic performance by regulating charge transfer and intermediate adsorption. For instance, TiO 2 exhibits corrosion resistance and inherently suppressed hydrogen evolution reaction (HER) activity, which is essential for nitrate reduction reaction (NO 3 RR). However, its poor conductivity restricts the reaction kinetics. Herein, we address this issue by engineering metallic dititanium oxide (Ti 2 O) through Ti–Ti bond formation within [OTi 6 ] octahedra, giving rise to polarized [Ti–Ti–O–Ti] motifs. This polarized oxide support enhances conductivity and triggers local electron redistribution. Integrating Cu single atoms onto the polarized Ti 2 O support achieves a current density of 233 mA cm –2, a Faraday efficiency of 91.26%, and a NH 3 yield rate of 19.16 mg h –1 cm –2 . Combined experimental and theoretical analyses demonstrate that [Ti–Ti–O–Ti] motifs accelerate the water-to-*H conversion, whereas Cu δ+ sites stabilize the adsorption of key intermediates. Their synergistic interplay enables efficient ammonia electrosynthesis on Ti 2 O–Cu electrode. This work pioneers polarity-engineered oxide support as a versatile platform for electrocatalyst design toward ammonia production.